Redline 75W90NS (Non Slip) full synthetic GL-5 gear oil contains no friction modifiers, which allows shifts to be made faster and easier under extreme cold and heat, due to faster synchro engagement. It provides superior protection for your gearbox/differential under track and street conditions. Is your 1st or 2nd gear synchro wearing out? Hard to shift on cold days? You'll definitely notice a difference when you switch to this Non Slip gear oil. 75W90NS is not recommended for use in "clutch-type" Limited Slip differentials/transaxles without the use of Redline Friction Modifier. This is due to the fact it has no friction modifiers, needed for correct limited slip clutch plate engagement. If you want the superior gear engagement of 75W90NS but are running a clutch type limited slip transaxle, we carry Redline Friction Modifier in our Lubricants section.